SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c087379a769cc5d6589116f6ab2a46819222e5d73a1833347c257f7adc80e4b4' 
  AND token = 'fFRYClUsYGZeDxaiFktn/mEsh56hh/fW3UJ3CMhJW4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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