SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '241070a57a2aa51ad3673cd68179d6b3fb7275ecd38f397b43aeed5c011ed356' 
  AND token = '9HAP50nqb05+a/ipGHUtDygQaXFYf08l/p0ztzEHpnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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