SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a9dcbbe27d95897c430eb14b468074c17317e9bb600829e53c1399d42937955' 
  AND token = 'T4plXuP3RASagDnOuRLm8KlEkJAs+PaHhmFRagEeF7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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