SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '637907699cc15329860563a0582a59100c9f55f04b42ff7b2f662d63b2b57741' 
  AND token = 'ER/Ql9YMVVY97La7moCBJOHzXjC7rbXQl6Zm8EMIbYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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