SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e51835fefc10f0d153bd2a2bf7c9cd01039c5be84c4bd77c06d6be232460761e' 
  AND token = 'DyTfPe0d8mJen7oFvhJogVfgazqvtZ13X/uvjPtqB+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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