SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abd28451931e545f6c301070413d2ed1b80774b2984b565b590de556f3cbd7c4' 
  AND token = 'bnd+Qg9aFL5UPPdxwdKfRriQMzrDLcVedEoe18WHebU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}