SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e79babcffda6d538803969e731776371e52289d0f3d841061a6e46e5b0eb54a' 
  AND token = 'Wtk2NMBiMh0lu3pUqnkLQdu0NlcddEOUncXQEn1KLb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}