SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1789219134ec6ba4f11cedfc15b6cff3edc87f217920d9502059699d5a4c2572' 
  AND token = 'iFvWbqZlyKkeRBJndwi16ri1T7omzyeSRs5GvTxADXE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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