SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2028ad06aa7da7f5a979e3bfa06f920ca3321ea596147c5dc597ddfbad4897b' 
  AND token = 'jEcx10r0yMCmzF9oQ1W7gSCUVRVJJwC+wd0is/qKucQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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