SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fad286d220fbf1ae904ac4acae107152b682a11f32877788d764eb1f50f7e054' 
  AND token = 'AAPb1ygUQD6HjUSqrcC8f8BKfBfGqFlrf4fIcJovJhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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