SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb59549263e83dcd675bc319178b691d6a3c2229eabc3428c19e227fd877f088' 
  AND token = 'QeLrFbvcvQcGKsxUiBmptdJ0kigoyfbPxtPiqoWiTfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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