SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2549382ba0d301bda9646b227b26747893064d1d1a16f6b53f8a06369fdeb5c' 
  AND token = 'lNu6PAyhga06B4oo65HGdlqBMMMrCMIrfR3SqxBik0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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