SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1a2e71f5e91a7580bd3b7374820cd55c5b147175c45fdd3c88336232ef67242' 
  AND token = 'Mn9Evq+KQQLWhtRYwqPCrqvALInCf9NxLV7pe8xAp9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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