SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bed509ab12931bcd0c33edf2b41b9974c94980da6cd545da0c112ca099f63a0a' 
  AND token = 'o3E9yi0bnUxd4OyQlf0DXv2CzQkCtmqlGq9vfYhhjhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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