SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6821746b9bee870f84222033ce93c98aa3c75bbeeb10f15d726306acd5fbfd3' 
  AND token = 'LMbcRRfHlDakDnOANWrWNQa26Ix/hh1Sl2FLI9l3ft0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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