SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee875580d3130f3abe8d24808f6ed42fb2b4469a3adc9c81ed537f83fd2558c5' 
  AND token = '8ddS1xsuE52PzXZ4cO7FZ0wjb+ln9wrCZunCZ+rpV/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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