SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1877b9ac34c70f554838589953d9bf46226b1f0a38b4a33a156a968eb2730810' 
  AND token = 'mmGHBM4dEWgVwMKZ3yxKnk6shYzew7qFtVUACSNG6lE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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