SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ed0751a69bd190cd436b0ccb1afb20e1cae0bf7213028f1be4621eca2f34890' 
  AND token = 'qPzyjMhlmCv7LuITHv3e1JYwllLqLLxZsorGViSIPDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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