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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f0d7457b3406c2138cc27c863e29cf7dd7dbae50b48aa457d06ca2533615d80c' 
  AND token = 'ytv+1SV8uWJ2e7Fj/m6HCF3hvTFPkVH0sW9OUD7PyLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}