SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59dd742d2b07103de58f2aaf5fe68d51a790bc694ca14bad61d05039cd331884' 
  AND token = 'QR/W8YR0eUkqEMuUkihd2gnW+jvprT3G3jDXFLzPoe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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