SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1605b0751c1b6f59dc00568306e0b85756416b30f5a58dc705d37846155fca73' 
  AND token = 'NXiGA7sYEn1+2eMEdSDfSAIBW1mJMEES7Hr0DD00SB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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