SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15295ce68b652dfb8a3e735e52ce41f09b6feedeffa0701b277251a356fd34f8' 
  AND token = 'tStmoWwhxNPcBV4EW98Z+E9MWIhM61fNVPBV1VIlHSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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