SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f796956abe3f25c49db21aa43ecbea5398a780172cc2b2c44753a1e8c18aed61' 
  AND token = 'NL6eAkZYhPpjCZJMmqi3YQAzfLbbAb7FBwQJSkxdrxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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