SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fe2075a4d6ad010c43512b96abfc657fee7016d608bb89c376e68cbba7fc15c' 
  AND token = '5tKS/xih3OwqjQQbQ6ilCPqVrnyTQTZH3ejvPHxnl30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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