SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78aed5aedfd4795cfde9d420d23e7fe26be887328099d5e0434982efcec3a359' 
  AND token = 'ew579FnRxIqRRvOaXtLBXn1PynYoZruLQArG1DnrhUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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