SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbd0f1e67a2aded86887686a9c1099a1631351e405f91136ea07e279d87ffcd8' 
  AND token = '0fHgWukZriC2K96u+oi1RDRTF/IBvcf3Qd/Yb4zvmFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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