SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76191a142e34aa39873024026d50dca53463073da48a8671e96687151d2d94c4' 
  AND token = 'cc+MoZFuvTdlN39I28UdIfIy+Vhd7XCAfVly/T9RmQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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