SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d63690f76ec1e102eacf565c78170bea5c036d5057ab7b9531c52334fe483ac' 
  AND token = 'HRdLUEfcej1ZZLLD79gwM2RT66e19awqnOqGRW5iLEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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