SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f00a9f0bc61e17023c3b437adca4faecac819230557fe29953bf3ad9e48ec0a3' 
  AND token = 'dQ2gOwcopcK/LN1BMBeFeMxLUK5YslMCjKUYWSwn/xo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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