SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f710bcb932f8585c711d9c685d11868190afceffbcf40ae865f6d1f1721650a2' 
  AND token = '7TmJipOQXHEmBRPjU42N3j0D56zdkAwcdUwozsV7S0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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