SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b5827589b65c541c65512f86536679abf61830eb8f25e7538f823086c45c372' 
  AND token = 'AbqSXtxSi4uqyPI4evA4yis83BFQ2plOfJUuc2DyJFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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