SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3fc187ac59f6b2dad31da4a9dff9572a6cb2a4db41e6799c6c3be268d8679fe' 
  AND token = 'wCns/cptH3KzxYWYUwROdUM0An9sCCRkgPA3qTCaIWc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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