SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ca3f1c8aec932f398df63be519f3b367b12d4c133b27ffc8ea676b2b398ca2d' 
  AND token = 'LaR1gXJDbdwppvgFyu8nZn1jVsjzWKb2b1wEZGZHSyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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