SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90cfeca1aa591ba0cc039586b3bcb1a4e53200932674e36e19c9d896db5f1292' 
  AND token = 'CLdv/L6eLFtCbrlQtBaBIoBY1dpWtV1+FbY7RrUF5WY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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