SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '306f3404ee5937001e4de3bca2d0e73373d51f2b55bee0bc221f3d4c412ca445' 
  AND token = 'uhcyXHueAvFgxtDFA2nbo/F2suCJRsz/PajGi72gWU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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