SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '962496cac1c6887a40ac0c8ff4dc71eda823a9631a590bc3e77f71513a78372c' 
  AND token = 'xOlc/euBqUzLRVQRH55V3Ge4AhyuKNu2jggeb8HfG8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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