SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5bfcf1411b2c8eb8a4b85d96273d2989dc9e0b2759959da13333bfa6ab1643a' 
  AND token = '7hjInhzaA6w2iS3vMJnGvX7aWxv6yKq8eTNTvZ5nlDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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