SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91c2fdeb2667e4caa4845b27f730e7c37b1c6db1aa8a98edadb9f9dacca868ca' 
  AND token = '7HO2TobhnGjOUNYTvmIdoBv0u3G70NhwjPXwL8Hiv80=' 
  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"
    }
  }
}