SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e3f2b10e5297a8030105825c5f757972ea9a551a5000057c31dfaece068ac982' 
  AND token = 'RD5POa5oWtLOqb8lrW3RWaOLrGrIlDoXHJgcXFNZ1ko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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