SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e31938ec8401680593d1c1b6ce3fb99e6c90db55689928fefacfc7cb82c4436a' 
  AND token = 'dCI8dxqqY6jdVw1ZQm1gH4Pa1kOtP/AZALtZkFzTEgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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