SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9ae635994b3c5211d5e0215da1c821c479a6dc517eda1429bacfd52f824a010' 
  AND token = 'ocKeTXQhLfmFhfrdHNiMy4RWQOdrySVAKRKihqr5gEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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