SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c2a38dc989b2953b4dda0635b42f16c874fc7606ae8926e3baa65032e56aff45' 
  AND token = 'ust6q393NX+CnQ75MfkB3ot0/ippJvgn+n0c1V0fk/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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