SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ed73351967e72df1a26a848f849c89a936c902f89b8fe1dec626eeb516b35da9' 
  AND token = 'DR85RFYmXnPUwPj188nBDbq+pFv5PHbICfy/aG+G/Ic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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