SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c719b9e6c042774f3283a09d4337a981f6fbe6bf5b85bb39555a7496a66363ae' 
  AND token = 'PyLOMJA5EU+/jPJAaEHTHaHaA62HoZ8okZlacRx8BCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}