SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c14620737ccc84f927b4883efd806ec1425f6d02af8caf30a82e1b53e27770c6' 
  AND token = 'fBEhbfPQW4fVXf90izWIECEE4Y4i7XBSJp+3VQiJA0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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